The embodiments described herein relate generally to electrical coils, and more particularly, to an electrical coil forming apparatus used in forming electrical coils for electrical machines.
Some electrical machines, such as a motor, typically include a stator having a plurality of electrical coils wound around a stator core. The stator core is generally formed by laminating a plurality of ring plates, and includes an inner circumference having a plurality of slots that extend along an axis of rotation of the electrical machine. In some stator designs, the electrical coils are coated with an electrically insulating enamel, and are wound around the stator core by inserting a portion of each stator coil into, and through, pairs of the slots.
Prior to insertion into the stator slots, the electrical coil is formed by winding a plurality of electrical wires within a winding tool. Some winding tools guide the electrical wires from a spool and around spindles. The spindles segregate the electrical wires into discrete bundles of electrical wires. The tool may continue to wrap the bundle of electrical wires around other circumferentially spaced spindles to form the electrical coil, which has a pair of opposing straight sections and a pair of opposing end turns.
Conventional electrical coils may include four bends within the straight sections and the end turns. This configuration, however, may lead to increased lengths of the straight portions and the end turns which may result in excess material needed for a particular application within the electrical machine. Further, the increased lengths at the end turns may interfere with motor components such as brackets and baffles. Moreover, the excess length and material may increase losses, such as resistive losses and thermal losses, during operation of the electrical coils. Further, during some insertion procedures, conventional coil configurations may increase the labor involved in pushing the electrical coils into the stator slots which may lead to negative ergonomic effects applied to the installer's hands and/or arms. After insertion of conventional electrical coils, the end turns may need to be further pushed and/or bent to make room for insertion of an adjacent electrical coil which may lead to cracking or other damage to the insulating coating and to further stress applied to the installer's hands and/or arms.